Support MatchStar naming (#2892)

CHANGELOG.md

@@ -57,6 +57,7 @@ Semantic versioning in our case means:
 - Fixes `DuplicateExceptionViolation` to work with `TryStar`
 - Fixes `TryExceptMultipleReturnPathViolation` to work with `TryStar`
 - Fixes `IncorrectExceptOrderViolation` to work with `TryStar`
+- Fixes that `MatchStar` was not checked in pattern matching name assignments
 
 ### Misc
 

tests/test_visitors/test_ast/test_naming/conftest.py

@@ -176,6 +176,12 @@ def container():
         ...
 """
 
+match_star = """
+match some_value:
+    case [*{0}]:
+        ...
+"""
+
 # This is the only case where we don't allow unused variables.
 match_as_explicit = """
 match some_value:
@@ -246,6 +252,7 @@ def container():
         match_variable,
         match_as_explicit,
         match_inner,
+        match_star,
     }
 
 _FOREIGN_NAMING_PATTERNS = frozenset((

wemake_python_styleguide/compat/nodes.py

@@ -12,6 +12,7 @@
 if sys.version_info >= (3, 10):  # pragma: py-lt-310
     from ast import Match as Match
     from ast import MatchAs as MatchAs
+    from ast import MatchStar as MatchStar
     from ast import match_case as match_case
 else:  # pragma: py-gte-310
     class Match(ast.stmt):
@@ -26,6 +27,11 @@ class MatchAs(ast.AST):
         name: Optional[str]  # noqa: WPS110
         pattern: Optional[ast.AST]
 
+    class MatchStar(ast.AST):
+        """Used to declare `[*rest]` and `{**rest}` patterns."""
+
+        name: Optional[str]
+
 if sys.version_info >= (3, 11):  # pragma: py-lt-311
     from ast import TryStar as TryStar
 else:  # pragma: py-gte-311

wemake_python_styleguide/compat/types.py

@@ -3,7 +3,10 @@
 
 from typing_extensions import TypeAlias
 
-from wemake_python_styleguide.compat.nodes import TryStar
+from wemake_python_styleguide.compat.nodes import MatchAs, MatchStar, TryStar
 
 #: When used with `visit_Try` and visit_TryStar`.
 AnyTry: TypeAlias = Union[ast.Try, TryStar]
+
+#: Used when named matches are needed.
+NamedMatch: TypeAlias = Union[MatchAs, MatchStar]

wemake_python_styleguide/violations/best_practices.py

@@ -1655,7 +1655,7 @@ class BlockAndLocalOverlapViolation(ASTViolation):
     2. Functions and async functions definitions
     3. Classes, methods, and async methods definitions
     4. For and async for loops variables
-    5. Except for block exception aliases
+    5. Except block exception aliases
 
     We allow local variables to overlap themselves,
     we forbid block variables to overlap themselves.

wemake_python_styleguide/visitors/ast/naming/validation.py

@@ -5,7 +5,7 @@
 from typing_extensions import final
 
 from wemake_python_styleguide.compat.functions import get_assign_targets
-from wemake_python_styleguide.compat.nodes import MatchAs
+from wemake_python_styleguide.compat.types import NamedMatch
 from wemake_python_styleguide.constants import (
     SPECIAL_ARGUMENT_NAMES_WHITELIST,
     UNREADABLE_CHARACTER_COMBINATIONS,
@@ -231,6 +231,10 @@ def _ensure_case(self, node: AnyAssign, name: str) -> None:
     'visit_AsyncFunctionDef',
     'visit_Lambda',
 ))
+@alias('visit_named_match', (
+    'visit_MatchStar',
+    'visit_MatchAs',
+))
 class WrongNameVisitor(BaseNodeVisitor):
     """Performs checks based on variable names."""
 
@@ -281,8 +285,16 @@ def visit_ClassDef(self, node: ast.ClassDef) -> None:
         self._class_based_validator.check_attribute_names(node)
         self.generic_visit(node)
 
-    def visit_MatchAs(self, node: MatchAs) -> None:  # pragma: py-lt-310
-        """Check pattern matching in a form of `case ... as NAME`."""
+    def visit_named_match(self, node: NamedMatch) -> None:  # pragma: py-lt-310
+        """
+        Check pattern matching.
+
+        In a form of
+        - `case ... as NAME`
+        - `case [*NAME]`
+        - `case {**NAME}`
+
+        """
         if node.name:
             self._regular_validator.check_name(node, node.name)
         self.generic_visit(node)